惜分飞

DB2中schema管理

发表于 2012 年 4 月 12 日由惜分飞

0.DB2版本信息

[db2inst1@xifenfei ~]$ db2level
DB21085I  Instance "db2inst1" uses "32" bits and DB2 code release "SQL09050" 
with level identifier "03010107".
Informational tokens are "DB2 v9.5.0.0", "s071001", "LINUXIA3295", and Fix Pack 
"0".
Product is installed at "/opt/db2/V9.5".

1.显示syscat.schemata视图结构

[db2inst1@xifenfei ~]$ db2 "describe table syscat.schemata"

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
SCHEMANAME                      SYSIBM    VARCHAR                    128     0 No    
OWNER                           SYSIBM    VARCHAR                    128     0 No    
OWNERTYPE                       SYSIBM    CHARACTER                    1     0 No    
DEFINER                         SYSIBM    VARCHAR                    128     0 No    
DEFINERTYPE                     SYSIBM    CHARACTER                    1     0 No    
CREATE_TIME                     SYSIBM    TIMESTAMP                   10     0 No    
REMARKS                         SYSIBM    VARCHAR                    254     0 Yes

2.查询当前存在schema

[db2inst1@xifenfei ~]$ db2 "select SCHEMANAME,owner,CREATE_TIME from syscat.schemata"

SCHEMANAME                 OWNER                      CREATE_TIME               
------------            ------------                   ----------------------------
SYSIBM                     SYSIBM                     2012-03-25-15.07.07.196612
SYSCAT                     SYSIBM                     2012-03-25-15.07.07.196612
SYSFUN                     SYSIBM                     2012-03-25-15.07.07.196612
SYSSTAT                    SYSIBM                     2012-03-25-15.07.07.196612
SYSPROC                    SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMADM                  SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMINTERNAL             SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMTS                   SYSIBM                     2012-03-25-15.07.07.196612
NULLID                     SYSIBM                     2012-03-25-15.07.23.011671
SQLJ                       SYSIBM                     2012-03-25-15.07.54.575637
SYSTOOLS                   DB2INST1                   2012-03-25-15.09.01.964744

  11 record(s) selected.

3.显示创建schema

[db2inst1@xifenfei ~]$  db2 "create schema xifenfei"
DB20000I  The SQL command completed successfully.

[db2inst1@xifenfei ~]$ db2 "select SCHEMANAME,owner,CREATE_TIME from syscat.schemata"

SCHEMANAME                 OWNER                      CREATE_TIME               
------------            ------------                  ----------------------------
SYSIBM                     SYSIBM                     2012-03-25-15.07.07.196612
SYSCAT                     SYSIBM                     2012-03-25-15.07.07.196612
SYSFUN                     SYSIBM                     2012-03-25-15.07.07.196612
SYSSTAT                    SYSIBM                     2012-03-25-15.07.07.196612
SYSPROC                    SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMADM                  SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMINTERNAL             SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMTS                   SYSIBM                     2012-03-25-15.07.07.196612
NULLID                     SYSIBM                     2012-03-25-15.07.23.011671
SQLJ                       SYSIBM                     2012-03-25-15.07.54.575637
SYSTOOLS                   DB2INST1                   2012-03-25-15.09.01.964744
XIFENFEI                   DB2INST1                   2012-04-03-12.01.12.724932

  12 record(s) selected.

4.隐式创建schema

[db2inst1@xifenfei ~]$ db2 "create table xff.t_xifenfei(id int,name varchar(100))"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "select SCHEMANAME,owner,CREATE_TIME from syscat.schemata"

SCHEMANAME                 OWNER                      CREATE_TIME               
------------            ------------                 ----------------------------
SYSIBM                     SYSIBM                     2012-03-25-15.07.07.196612
SYSCAT                     SYSIBM                     2012-03-25-15.07.07.196612
SYSFUN                     SYSIBM                     2012-03-25-15.07.07.196612
SYSSTAT                    SYSIBM                     2012-03-25-15.07.07.196612
SYSPROC                    SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMADM                  SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMINTERNAL             SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMTS                   SYSIBM                     2012-03-25-15.07.07.196612
NULLID                     SYSIBM                     2012-03-25-15.07.23.011671
SQLJ                       SYSIBM                     2012-03-25-15.07.54.575637
SYSTOOLS                   DB2INST1                   2012-03-25-15.09.01.964744
XIFENFEI                   DB2INST1                   2012-04-03-12.01.12.724932
XFF                        SYSIBM                     2012-04-03-12.03.12.581260

  13 record(s) selected.

隐式创建schema的所属用户会是SYSIBM(存放系统数据字典表SCHEMA)

5.删除schema

[db2inst1@xifenfei ~]$ db2 "drop schema xff"
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0104N  An unexpected token "END-OF-STATEMENT" was found following "drop 
schema xff".  Expected tokens may include:  "RESTRICT".  SQLSTATE=42601

[db2inst1@xifenfei ~]$  db2 drop schema xff restrict 
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0478N  DROP, ALTER, TRANSFER OWNERSHIP or REVOKE on object type "SCHEMA" 
cannot be processed because there is an object "XFF.T_XIFENFEI", of type 
"TABLE", which depends on it.  SQLSTATE=42893

[db2inst1@xifenfei ~]$ db2 "drop table xff.t_xifenfei"
DB20000I  The SQL command completed successfully.

[db2inst1@xifenfei ~]$  db2 drop schema xff restrict 
DB20000I  The SQL command completed successfully.

[db2inst1@xifenfei ~]$ db2 "select SCHEMANAME,owner,CREATE_TIME from syscat.schemata"

SCHEMANAME                 OWNER                      CREATE_TIME               
------------            ------------                 ----------------------------
SYSIBM                     SYSIBM                     2012-03-25-15.07.07.196612
SYSCAT                     SYSIBM                     2012-03-25-15.07.07.196612
SYSFUN                     SYSIBM                     2012-03-25-15.07.07.196612
SYSSTAT                    SYSIBM                     2012-03-25-15.07.07.196612
SYSPROC                    SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMADM                  SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMINTERNAL             SYSIBM                     2012-03-25-15.07.07.196612
SYSIBMTS                   SYSIBM                     2012-03-25-15.07.07.196612
NULLID                     SYSIBM                     2012-03-25-15.07.23.011671
SQLJ                       SYSIBM                     2012-03-25-15.07.54.575637
SYSTOOLS                   DB2INST1                   2012-03-25-15.09.01.964744
XIFENFEI                   DB2INST1                   2012-04-03-12.01.12.724932

  12 record(s) selected.

删除schema需要使用restrict关键字,而且该schema中无对象存在.

在DB2中的schema的概念和ORACLE中的概念有着本质的区别：在ORACLE中schema和用户是同一个;在DB2中schema不一定是用户,因为db2内部没有用户的概念,连接用户必须是操作系统用户.

发表在 DB2 | 评论关闭

DB2中产生唯一值三种方式

发表于 2012 年 4 月 12 日由惜分飞

一.Genearate_unique函数

[db2inst1@xifenfei ~]$ db2 "create table xifenfei.t_gu(custno char(13) for bit data,
> custname varchar(16))"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$  db2 "insert into xifenfei.t_gu values
> (generate_unique(),'www.xifenfei.com'),(generate_unique(),'xifenfei')"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "select * from xifenfei.t_gu"

CUSTNO                        CUSTNAME        
----------------------------- ----------------
x'20120403054630527862000000' www.xifenfei.com
x'20120403054630527940000000' xifenfei        

  2 record(s) selected.

generate_unique是按照国际标准时间(UTC)生成的当前时间戳加上当前数据库分区号，包含13个字节的字符串。如果调整了系统时间可能会出现重复

二.序列(Sequence)

[db2inst1@xifenfei ~]$ db2 "create sequence xifenfei.xff_seq
> as bigint
> start with 1
> increment by 1
> no maxvalue
> cycle
> cache 10"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "create table xifenfei.t_seq(xff_id bigint,
> custname varchar(16))"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "insert into xifenfei.t_seq values(nextval 
> for xifenfei.xff_seq,'www.xifenfei.com'), (nextval for xifenfei.xff_seq,'xifenfei')"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "select * from xifenfei.t_seq"

XFF_ID               CUSTNAME        
-------------------- ----------------
                   1 www.xifenfei.com
                   2 xifenfei        

  2 record(s) selected.

和ORACLE的sequence基本相同，只是在oracle中是sequence.nextval这里改为了nextnvl for seqence

三.自增字段

--1.generated always as identity方式(不能人工干预插入数值)
[db2inst1@xifenfei ~]$ db2 "create table xifenfei.t_ind_a(xff_id bigint not null generated always 
> as identity(start with 10,increment by 1,minvalue 10,maxvalue 1000000,no cycle,nocache,no order),
> custname varchar(16))"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "insert into xifenfei.t_ind_a(custname) values('www.xifenfei.com')"
DB20000I  The SQL command completed successfully.
--指定值插入失败
[db2inst1@xifenfei ~]$ db2 "insert into xifenfei.t_ind_a(xff_id,custname) values(11,'XIFENFEI')"
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0798N  A value cannot be specified for column "XFF_ID" which is defined as 
GENERATED ALWAYS.  SQLSTATE=428C9
[db2inst1@xifenfei ~]$ db2 "select * from xifenfei.t_ind_a"

XFF_ID               CUSTNAME        
-------------------- ----------------
                  10 www.xifenfei.com

  1 record(s) selected.

--1.generated by default as identity方式(可以人工干预插入数值)
[db2inst1@xifenfei ~]$ db2 "create table xifenfei.t_ind_d(xff_id bigint not null generated by default 
> as identity (start with 10,increment by 1,minvalue 10,maxvalue 1000000,no cycle,nocache,no order),
> custname varchar(16))"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "insert into xifenfei.t_ind_d(custname) values('www.xifenfei.com')"
DB20000I  The SQL command completed successfully.
--指定值插入成功
[db2inst1@xifenfei ~]$ db2 "insert into xifenfei.t_ind_d(xff_id,custname) values(11,'XIFENFEI')"
DB20000I  The SQL command completed successfully.
[db2inst1@xifenfei ~]$ db2 "select * from xifenfei.t_ind_d"

XFF_ID               CUSTNAME        
-------------------- ----------------
                  10 www.xifenfei.com
                  11 XIFENFEI        

  2 record(s) selected.

这个功能和sql server/mysql的自增长列很相似，给出了两种方式选择，使得比它们更加灵活

发表在 DB2 | 评论关闭

ORACLE 十进制与二进制互转函数

发表于 2012 年 4 月 12 日由惜分飞

十进制转换二进制

CREATE OR REPLACE FUNCTION NUMBER_TO_BIT(V_NUM NUMBER) 
RETURN VARCHAR IS V_RTN VARCHAR(8);--注意返回列长度
  V_N1  NUMBER;
  V_N2  NUMBER;
BEGIN
V_N1 := V_NUM;
    LOOP
      V_N2  := MOD(V_N1, 2);
      V_N1  := ABS(TRUNC(V_N1 / 2));
      V_RTN := TO_CHAR(V_N2) || V_RTN;
      EXIT WHEN V_N1 = 0;
    END LOOP;
--返回二进制长度
 SELECT lpad(V_RTN,8,0) 
    INTO   V_RTN
    FROM dual;
return V_RTN;
end;

SQL> select NUMBER_TO_BIT(208) from dual;

NUMBER_TO_BIT(208)
-----------------------------
11010000

二进制转换十进制

CREATE OR REPLACE FUNCTION BIT_TO_NUMBER(P_BIN IN VARCHAR2) RETURN NUMBER AS
  V_SQL    VARCHAR2(30000) := 'SELECT BIN_TO_NUM(';
  V_RETURN NUMBER;
BEGIN
  IF LENGTH(P_BIN) >= 256 THEN
    RAISE_APPLICATION_ERROR(-20001, 'INPUT BIN TOO LONG!');
  END IF;
  IF LTRIM(P_BIN, '01') IS NOT NULL THEN
    RAISE_APPLICATION_ERROR(-20002, 'INPUT STR IS NOT VALID BIN VALUE!');
  END IF;
  FOR I IN 1 .. LENGTH(P_BIN) LOOP
    V_SQL := V_SQL || SUBSTR(P_BIN, I, 1) || ',';
  END LOOP;
  V_SQL := RTRIM(V_SQL, ',') || ') FROM DUAL';
  EXECUTE IMMEDIATE V_SQL
    INTO V_RETURN;
  RETURN V_RETURN;
END;

SQL> SELECT BIT_TO_NUMBER('11010000') FROM DUAL;

BIT_TO_NUMBER('11010000')
-------------------------
                      208

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DB2中schema管理

DB2中产生唯一值三种方式

ORACLE 十进制与二进制互转函数

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DB2中产生唯一值三种方式

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